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The things that are better left unspoken

a blog by Sander Berkouwer


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Activating Server Core

For years now Microsoft is using Windows Product Activation to protect its intellectual property from piracy. Windows Vista en Windows Server 2008 both sport Volume Activation 2.0. Although Server Core does not sport a full fledged Graphical User Interface, it doesn't escape the claws of Windows Product Activation. In this post I'll try to explain:

  • The way Windows Server 2008 Server Core installations install by default,
  • How to check the activation status
  • How to switch from KMS to MAK

It's especially important to look at activating your Server Core installation of Windows Server 2008, since you won't receive pop-ups or balloon tips stipulating how many days you may or may no longer have to continue your usage of the product.  

All the commands shown here are not limited to Server Core. The commands can also be used to activate Full installations of Windows Server 2008 and even Windows Vista installation from the command line.


Default Activation behavior

A Server Core installation of Windows Server 2008 can show different Windows Product Activation behavior depending on the source of the installation media and the way Windows Server 2008 was installed.

Typical installation media

Subscription media

Typically ISOs that were downloaded from MSDN subscriptions, TechNet subscriptions, Volume License programs or the Partner extranet and used to install Windows Server 2008 will search for a Key Management Services (KMS) Server on your network.

Original Equipment Manufacturers (OEM) media

Original Equipment Manufacturers like Dell, HP and IBM will preinstall Windows Server 2008 on certain models. These servers will typically be installed with an activated OEM copy of Windows Server 2008. You won't typically need to enter a product key or activate the server when you reinstall it with the supplied OEM media.

Full Packaged Product media

Full Packaged Products (FPPs) of Windows Server 2008 will typically be shipped with a Certificate of Authenticity and a product key. You need the product key to install Windows Server 2008 and you will typically need to activate Windows Server 2008 within 60 days of installation.

Microsoft Knowledgebase article 948472 shows how to extend the activation grace period as far as 240 days, if needed.

Installation method

As described above some installation media will not ask for a Windows product key when you install Windows Server 2008. In that case the installation screen to enter the product key will not appear. Other packages of Windows Server 2008 ask you to enter a Product Key at installation time (although not required) along with the option to activate the product after installation.

Automatic activation

When presented with the Product Key screen during installation of Windows Server 2008 you can chose whether to automatically activate the product or not. As I depicted above making the right choice is important at that stage, since you won't find any information on your desktop regarding product activation. You'll have to look for it yourself when you chose not to activate automatically.

Checking the activation status

On a full installation of Windows Server 2008 you can check the status of Windows Product Activation in the System properties. You can get there in a multitude of ways:

  • Press Start, type System, and then select System from the search list
  • Press Start, right-click Computer and select Properties from the context menu
  • Press Start, click Configuration Panel, double click System.
  • Press the start button on your keyboard and the pause/break key at the same time.

You can see your product key, your activation status and the number of days left before activation at the bottom of the screen under Windows Activation. In certain scenarios a link is provided to change the product key.

Checking the status of Windows Product Activation is slightly harder on Server Core installation, compared to Full installations of Windows Server 2008, although the command is remarkably simple:

start /w slmgr.vbs -dli

Where dli stands for display license information. Although the start /w part is optional I recommend using it because otherwise you might get the idea the command isn't doing anything, while in fact it just takes a long time to complete.

If you want to see the status of the three licensing options use the dlv instead of the dli switch with slmgr.vbs. The dli switch will only display license information on licensing methods that are in use.

Activating Server Core

Depending on the output of the command you entered to check the status you can activate your Server Core installation in a couple of ways:

Activating with a pre-entered product key

When you entered a product key when you installed Windows Server 2008 but didn't select the option to activate automatically you need to give a command to start activation:

start /w slmgr.vbs -ato

When done check the status of Windows Product Activation again.

Entering a product key and activating

When you choose to install Windows Server 2008 without entering a product key at the product key screen you need to enter a product key and activate your installation after that. To enter your 25-digit product key and activate afterwards, simply type the following commands:

start /w slmgr.vbs -ipk ABCDE-FGHIJ-KLMNO-PQRST-UVWXY
start /w slmgr.vbs -ato

Where you need to replace ABCDE-FGHIJ-KLMNO-PQRST-UVWXY with the Windows product key from your Certificate of Authenticity. When done check the status of Windows Product Activation again.

Switching from KMS to MAK

When the string VOLUME_KMSCLIENT appears as output of the slmgr.vbs -dli command, it means your Server Core installation is using KMS activation, which is one of the activation options in Volume Activation 2.0. If you don't have a KMS server or know the server isn't going to be in the vicinity of your KMS Server every week you're going to have a problem.

You can manually activate your installation of Windows Server 2008 by entering your Multiple Activation Key (MAK). You can find your Multiple Activation Keys (MAKs) below the list with other product keys when logged in to your MSDN Subscription.

To switch from KMS to MAK simply enter your Multiple Activation Key and activate afterwards. The commands are the same as in the previous activation method:

start /w slmgr.vbs -ipk ABCDE-FGHIJ-KLMNO-PQRST-UVWXY
start /w slmgr.vbs -ato

Setting different KMS settings

A Windows Server 2008 installation will try to reach a Key Management Services (KMS) Server every 10.080 minutes (every week) to check its license. By default Windows Server 2008 and Windows Vista, configured as KMS clients will lookup the KMS Server in DNS requesting the contents of the SRV record for _vlmcs._tcp and connect using TCP 1688.

Although you can't change this time skew, you can edit the name and portnumber of the KMS server your Windows Server 2008 installation will try to reach. Particularly in scenarios where security is at stake you can manually enter KMS Server information to your Windows Server 2008 installation using the following command:

start /w slmgr.vbs -skms fqdn.of.the.KMS.server[:port]

Where fqdn.of.the.KMS.server can be replaced with the Fully Qualified Domain Name (FQDN) of your Key Management Services (KMS) Server. Optionally you can specify a port to connect with when you don't want communication over TCP 1688. Of course your KMS Server on the other side must be configured properly as well.

To reset your KMS client to default settings use the following command:

start /w slmgr.vbs -ckms

Activating without Internet

Server Core might be used in environments without Internet access. I know this sounds silly but I know of a few and I don't go out as much as some of my fellow bloggers do...

In this scenario you activate your Server Core installation by first running:

start /w slmgr.vbs –dti

Write down the Installation ID, which consists of nine blocks of six digits. After that call your local Microsoft Activation Call Center and write down the activation key, which consists of eight blocks of six digits you receive in response to punching in the Installation ID.

Now run: 

start /w slmgr.vbs –atp GUID ActivationID

Where ActivationID must be notated as one long 48-digit string.

Run the command to check your licensing information (above) to confirm your Server Core installation was activated properly.

Switching from MAK to KMS

Another scenario might be you want to switch back from using a Multiple Activation Key (MAK) to Key Management Services (KMS) Servers. This might be due to the fact you want more control over your in-use licenses.

To switch you need to enter your KMS product key. If you were paying attention before you might have already found the problem: Windows Server 2008 media that use KMS by default, don't allow you to enter a product key, nor do they have a Certificate of Authenticity with a product key on it... now where do you get the KMS product key!?

That's easy. It's located on the Windows Server 2008 DVD/ISO in the file pid.txt in the sources folder. To switch from MAK to KMS simply enter your Multiple Activation Key and activate afterwards. The commands are the same as for switching from KMS to MAK:

start /w slmgr.vbs -ipk ABCDE-FGHIJ-KLMNO-PQRST-UVWXY
start /w slmgr.vbs -ato

Where ABCDE-FGHIJ-KLMNO-PQRST-UVWXY is your KMS product key.When done check the status of Windows Product Activation again.



Windows Product Activation can sneak up on you when using Server Core installation of Windows Server 2008. Be sure to activate your copy of Windows.

Further reading

Microsoft Activation Centers Worldwide Telephone Numbers 
Volume Activation 2.0 for Windows Vista and Windows Server 2008 
Volume Activation 2.0 Technical Guidance
CompDocs - Windows Vista KMS Activation
Windows Software Licensing Management Tool (Vista SLMGR.vbs) Usage Hack Guide 
TechNet forums - Install and activate core server without web
TechNet forums - Convert Windows Server 2008 Server from MAC to KMS
TechNet forums - Activation problems
How to extend the Windows Server 2008 evaluation period
Windows Server 2008 Enterprise licensing 
Volume Activation Management Tool (VAMT) 1.1 
[WMV] Windows Server 2008 KMS Setup Demonstration 
How to move Vista from MAK back to KMS client 
Confused about Windows Vista Volume Activation 2.0?
Windows Vista key management is now available on Windows Server 2003 SP1 
Using Server Isolation to Protect Your KMS Servers  
Product Activation Comes to Business

Posted: Tuesday, April 01, 2008 9:21 AM by Sander Berkouwer


The things that are better left unspoken said:

There are a couple of ways to install Windows Server 2008. When you're lucky enough to get your hands on a physical copy of a Windows Server 2008 DVD you can use that, but what if your target system doesn't have a DVD player? What if you want to install it in a different way?  What if you wanted to save some time? Read on!

# May 1, 2008 2:58 AM

TrackBack said:

A little searching was required in order to find the right command line commands.

We found them on Sander Berkouwer's blog "The things that are better left unspoken" Activating Server Core.

# May 6, 2008 1:13 AM

[HELP] Aktivasi Online win7 Ori Gagal - Page 2 - CHIP Forum said:

The error 0xC004C008 means that the KMS key has exceeded the activation limit. KMS keys will activate up to 10 times on six different computers.
# December 26, 2009 5:42 PM

Steve Dolphin » Blog Archive » Making a KMS in Server Core 2008 R2 said:

There are LOTS of guides about how to make a KMS (Key Management Server) in Server Core 2008, but not that many about how to do it in 2008R2. The process seems to be much the same, but some of the guides have outdated switches and commands which do not work.

  • From your command prompt register your KMS key:
    slmgr /ipk <your key>
  • Then attempt an automatic (over-the-internet) activation:
    slmgr /ato
  • That should work. If it doesn’t (mine didn’t) then you need to perform a manual activation instead. First you need to get the installation ID:
    slmgr /dti
  • Ring one of the Microsoft numbers and enter that huge number in six-digit-blocks as prompted, and then note the number it gives back to you in notepad or something similar.
  • Enter the activation code using:
    slmgr /atp <confirmation code>

Finally, to check the status of your KMS server you can use

  • slmgr /dlv
  • slmgr /dli

I did all this and then got a GUI-version of 2008 R2 to contact the KMS perfectly, however for some strange reason my other Core 2008 R2 installs are not working yet…

# June 7, 2010 6:04 PM

Activating Server Core 2008 R2 – Charles L'Abri Anderson said:

So, I’ve got my server core DC all up and running. Works like a champ, and I love the low overhead of the machine.

Time to activate.

Sander Berkouwer has a great write up over here that he wrote back in ’08.

# November 16, 2011 5:11 PM
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